OrganisationRequired Practical
Required Practical 4: Food Tests
Part of Enzymes in Digestion — GCSE Biology
This required practical covers Required Practical 4: Food Tests within Enzymes in Digestion for GCSE Biology. Enzyme structure and function, digestive enzymes, factors affecting enzyme activity, lock and key model, and practical investigations It is section 8 of 19 in this topic. Revise both the method and the reason for each step, because practical questions often test understanding rather than pure recall.
Topic position
Section 8 of 19
Practice
20 questions
Recall
25 flashcards
🧪 Required Practical 4: Food Tests
Testing for biological molecules in food samples:
Benedict's Test (Reducing Sugars)
- Reagent: Benedict's solution (blue)
- Method: Add Benedict's, heat in water bath (80°C)
- Positive result: Blue → green → yellow → orange → brick red
- Tests for: Glucose, fructose, maltose
Iodine Test (Starch)
- Reagent: Iodine solution (orange/brown)
- Method: Add a few drops to sample
- Positive result: Orange → blue-black
- Negative result: Stays orange
Biuret Test (Proteins)
- Reagent: Biuret solution (blue)
- Method: Add biuret solution to sample
- Positive result: Blue → purple
- Negative result: Stays blue
Emulsion Test (Lipids)
- Reagent: Ethanol and water
- Method: Dissolve in ethanol, then add water
- Positive result: White cloudy emulsion forms
- Negative result: Solution stays clear